Analysis of transconjugants and integration site
The presence of pIJ8600 in transconjugants of S. rimosus
R7 and M4018 was initially determined by PCR of the
0Æ8-kb tsr gene from several independent clones (data not
shown). To characterize the integration site, chromosomal
DNA was extracted from independent transconjugants of S. rimosus R7 and M4018 and digested with HindIII and
SacI, blotted onto nylon membranes and hybridized with
the labelled 2Æ05-kb HindIII⁄ SacI fragment of pIJ8600
(containing the attP region). When pIJ8600 was transferred
into S. rimosus, the left and right sides of attP
recombined with the corresponding sites of attB to yield
the hybrid att sites, attL and attR (Fig. 1a). Fragments of
2Æ7 kb and >10 kb were detected in transconjugants of
S. rimosus R7 (Fig. 1b, lanes 4–7) and M4018 (lanes
8–11), respectively